Collet



Jan. 25, 1949. M, STQNER 2,459,900

COLLET Filed June 20, 1945 2 Sheets-Sheet 1 INVENTOR. I ARTHUR MERRICK STONER ATTQRNEY Jan. 25, 1949. A. MKSTONER 2,459,900

I COLLET I Filed June 20, 1945 2 Sheets-Sheet 2 W iiiiii if z \v 48 L 49 IN V EN TOR.

\fl 4 ARTHUR MERRICK STONER ATTORNEY Patented Jan. 25, 1949 UNITED STATES F ATENT QFFEQE.

COLLET Arthur Merrick Stoner, West Hartford, Conn, as-

signor to The Jacobs Manufacturing Company, Hartford, Conn a corporation of Connecticut Application June 20, 1945, Serial No. 600,550

3 Claims.

Patent No. 2,346,706, issued April 18, 1944. The

range of adjustability of a collet constructed as described therein is limited to such an extent that it has been necessary to furnish a set of several collets-of different sizes for each chuck to adapt the chuck to the full range of tool or stock sizes within its capacity. The principal object of the present invention is to provide an improved collet which is adjustable over the entire range of sizes within the chuck capacity, to avoid the necessity of providing several collets for a given chuck.

. In a collet constructed according to the aforesaid patent, the resilient material substantially fills the spaces between the gripping members. Adjacent sides of proximate gripping members are so related or shaped that when the, resilient material is displaced by inward movement of the gripping members, it bulges inwardly and'outwardly like a block axially loaded, with little or no tendency to buckle or fold in one direction. Such of the resilient material as is displaced inwardly becomes interposed between the inner edges of the gripping members and the article gripped by them and limits their inward radial movement.

An object of this invention is to proportion and arrange the resilient material in relation to the spaces between adjacent sides of proximate gripping members regardless of the angularity between said sides, so that it is caused to buckle or fold upon itself as the spaces between the gripping members are decreased by the inward move ment of the latter and to provide ample room for receiving the folded resilient material, thus to attain a full range of adjustability of the gripping members for all tool or stock sizes within the capacity of the chuck.

1 This is a. continuation in part of a, copending application for patent Serial No. 521,097 filed by me February 4, 1944, in which I have specifically claimed one way of getting the desired folding effect by providin a sufiiciently wide angularity between adjacent sides of proximate gripping members to force the resilient materialoutwardly as the space between them is decreased by their inward movement, into a clearance space provided for its reception. In the present; application further structural modifications are shown and 56 7 described and I propose to claim also that the desired folding efiect may be attained by the shapev and proportion of the resilient material regardless of the angularity between adjacent sides of the gripping members.

Referring to the drawings: Figure l is a side elevation and Fig. 2 a front iew of a collet which is made according to and embodies the present invention. In these figures the gripping members are in the relative positions which they assume when the resilient material is in its normal at rest condition.

Fig. 3 is a side elevation of one of the gripping members shown in the preceding figures,

Fig. 4 is a diagrammatic front elevation, partly in section and on a larger scale, of a collet of modified construction. The relative positions of the gripping members and of the interconnecting resilient body when the collet is under maximum compression is indicated in dot-dash lines.

Fig. 5 is a view similar to Fig. 4 without any part shown in section, of another modified construction.

Fig. 6 is a similar view of a collet with eight sector-like gripping members, the adjacent sides of proximate members being flat and parallel.

Fig. '7 is a sectional end elevation of a part of the collet shown in Fig. 6 in its compressed condition.

Figs. 8, 9, l0 and '11 show in diagrammatic front elevations, embodiments of the present invention applied to three-jaw collets.

Fig. 12 is a sectional side elevation of a chuck of which a collet such as that shown in Figs. .1 and 2 is a part. In this figure the parts are in their open or non-clamping positions. It is to be understood that the collets shown in Figs. 4-11 may be used as a part of such a chuck. This Fig. 2 is included to show how the collets shown and described herein may be used.

In FigsQl-S and 8-12, 213 designates the rigid clamping members. These, in the particular form shown in all of the figures except Figs. 6

and '7, are flat metallic plates, beveled to form inner straight gripping edges 2| which are chamfered at their outer ends as at 22 to facilitate the insertion of a desired article, such as the shank of a tool. A part 23 of their outer edges is in clined to extend to a conical cam surface. of 'a' chuck. The rear outer edges 24 are parallel with the gripping edges 2|. The rear ends 25 are at right angles to the gripping edges. These plates are provided preferably with transverse orifices 26.

Q30 designates a body of resilient material which engages the threads 43'- on the body.

may be bonded to the sides of the gripping members and extends from each member to the proximate ones. Oil resistant synthetic rubber is a suitable material to use forthis purpose. When the plates are provided with the orifices 26, the

resilient material passes through them. The

front edge 3! of the body of resilient material is spaced from the front ends of the gripping members and its rear edge 32 is spaced from the rear} ends'25 of these members. In' the specific construction shown in Figs. 1 and 2, its outer sur-- faces 33 are fiat and are spaced from and parallel with the inclined outer edges 23 of the gripping members (see Fig. 1) {As shown in 2, it'si'nner surfaces 35 lie in a cylinder spaced inwardly from and parallel with the inner edges 2| of the gripping members.

The resilient material is molded or otherwise formed so that when it is in its normal condition it holds the gripping members in substantially radial positions, equally spaced angularly With the distance between their inner edges 2i some-,

a hollow portion 4!" with a cylindrical bore 42,

the forward part of which is internally threaded as at 43. 44 is a block longitudinally slidable in the bore 42. The front end of this block has a fiat transverse surface designated by A5.

table'in the block. The pin has enlarged heads i? which are eccentric to the axis of rotation of the pin and are seated in circular holes in the body W. 48 is. an externally threaded collar which has an internal cone shaped cam surface is. The collet is placed in the chuck back of the collar 48- with the rear ends of its gripping members seated on the surface 45 of the block 46.

When the collar d3 is screwed into the body 43 its cam surface d9 will move the gripping members into engagement with anything which is between them. They can be further tightened' by rotating the pin 68 to move the block 44 and the gripping members forwardly.

In Fig. 4 the outer surfaces 3 3A and the inner surfaces 35A of the resilient body 39A are some- What flattened curves and a radial slot is cut into-each of the inner surfaces 35A.

Thep'arts of the resilient body between the gripping members are so shaped as to cause them to fold outwardly when the collet is compressed The circle A in. this'figure and also in Figs. 5, 6,. 8-11, represents the diameter of the part of the conical'cam which engages the inner endscf the inclined surfaces 23 of the gripping members when the collet is not compressed. The smaller circle B in Figs. 4, 5,. 7-11 represents the diameter of the part of the conical cam whi'chiengages the same parts of the gripping members when the .th'emiindicated by similar lines.

In Fig. 5both the outer surfaces 343 and the inner surfaces 35B of the body 3 are flat and two slots 37 and 38 are cut into the surfaces 353';

These configurations cause the parts of theresilie'nt body'to fold outwardlyand the shape they This collar 46 is a transverse pin which passes through and is rotagrippi- 4 assume when the gripping. members are moved to their innermost positions is indicated by dot-dash lines. a

The folding effect may be attained regardless of the angularity between the sides of the gripping members. The adjacent sides of the sectorlike gripping members 20A in Figs. 6 and 7 are fiat and parallel. Betweenj them the resilient body is shaped as shown at'38C in Fig. 6 when the collet is open and is folded outwardly upon itself as shown at 30D in Fig. '7 when the collet is compressed in its gripping members'moved into the positions shown at 293.

I n' 8 the three flat gripping members are interconnected by a resilient body 30E, the outer surfaces 36E of which are flat and its inner surfaces E lie *in substantially semi-cylindrical surfaces. The shape into which these parts are folded when the collet is close'd'is indicated by dot-dash line's. v

In Fig; 9 longitudinal groovest 'iF and 35F are fled in the outer and inner surfaces respecthere body between the gripp Jhon the collet is closed, folds are-made in it as indicated by dot-dash lines both inwardly as by 1 and outwardly as natedby 0'. r

l9 if the parts of the resilientbodies ads? and 3 32-! between the gripping mem- 2e are in the form of comparatively thin tantially fiat connected leaves which fold to'-' gether bellows-fashion when the collets' are closed. In Fig. 10 there are four of these leaves, the outer ones of which 56 and 51 abut and may aiiixed to the adjacent sides of proximate members Between them the leaves 52, extend outwardly and join each other at acute angle The connecting ends of these ie'a'ves when the collet is closed permitting leaves to lie mere closely together, as indi- V sated by dot-dash lines.

showing.

.e modification shown in Fig. 11 is similar that in Fig. to but in this case there are four leaves of which the outer ones designated by 54 and 55 abut and may be affixed to the gripping members and the intermediate ones are designated by 55, 58 and-49] The operation is obvioijrsly'similar to that just described. 7 7

Sci? a1 unlike structures whichembody this invention have been illustrated and described to shew that it is no sense limited to any particular form and that the resilient body may be shaped in many forms to obtain the desired folding effect. It is also within the scope of the invention as disclosed in the aforesaid application fer patent Serial' No. 521,097 and in'the present case, to utilize boththe angularity between the sides of the" gripping members and the shape of the partsof the resilient body between the gripping members to obtain the desired folding result.

Various modifications inconstiuction, mode of operation, method and use of an invention may and do" occur to others, especially after benefitting fronrknowiedge of such a disclosure asthat herein presented of the principles involved, butthe invention itself is not confined to the present Icl'aim; V r V l. A collet of wide range for amachine toolc'h-u'ck having an internal conical cam surface,

" said collet comprising a plurality of tapered angui'any' spaced rigid gripping membersv symmetricgall'y disposed about the axis of the cam surface their inner and outer surfaces between the gripping members. I

2. A collet of wide range for a machine tool chuck having an internal conical cam surface,

said collet comprising a plurality of tapered angularly spaced rigid gripping members symmetrically disposed about the axis of the cam surface and being arranged to extend to and be engaged by the cam surface and being movable radially in concert toward and away from said axis, whereby the volume of the spaces between them is varied, non-compressible non-metallic struts of resilient material in said spaces based upon adjacent sides of proximate gripping members and connected to said members, said struts being of less radial extent than the gripping members with their outer surfaces spaced radially from the inner and outer surfaces of the gripping members to provide clearances into which the struts may fold, the medial portions of the struts in planes transverse to the axis of the cam sur- 7 face being displaced radially from planes through the centers of pressure imposed upon the bases of the gripping members by the inward radial movement of said gripping members, the adjacent sides of proximate gripping members being substan-- tially parallel, and means including the struts for inducing folding of said struts upon axial loading thereof.

3. A collet of wide range for a machine tool chuck having an internal conical cam surface, said collet comprising a plurality of tapered angularly spaced rigid gripping members symmetrically disposed about the axis of the cam surface and being arranged to extend to and be engaged by the cam surface and being movable radially in concert toward and away from said axis, whereby the volurneof the spaces between them is varied, non-compressible non-metallic struts of resilient material in said spaces based upon adjacent sides of proximate gripping members and connected to said members, said struts being of less radial extent than the gripping members with their outer surfaces spaced radially from the inner and outer surfaces of the gripping members to pro vide clearances into which the struts may fold, the medial portions of the struts in planes transverse to the axis of the cam surface being displaced radially outwardly from planes through REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,923,283 Stokes Aug. 22, 1933 2,346,706 Stoner Apr. 18, 1944 

